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<head><meta charset="utf-8"><title>I-prioritize #58355 Compiler panic when implementing recurs… · t-compiler/wg-prioritization/alerts · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/index.html">t-compiler/wg-prioritization/alerts</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html">I-prioritize #58355 Compiler panic when implementing recurs…</a></h3>

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<a name="220513933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220513933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220513933">(Dec 20 2020 at 10:35)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="3111">@WG-prioritization/alerts</span> issue <a href="https://github.com/rust-lang/rust/issues/58355">#58355</a> has been requested for prioritization.</p>
<h1><a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#assign-priority-to-unprioritized-issues-with-i-prioritize-label">Procedure</a></h1>
<ul>
<li>Priority?</li>
<li>Regression?</li>
<li>Notify people/groups?</li>
<li>Needs <code>I-nominated</code>?</li>
</ul>



<a name="220539301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539301">(Dec 20 2020 at 21:59)</a>:</h4>
<p>Seems like this first started ICEing in 1.24 -&gt; P-medium?</p>



<a name="220539342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539342">(Dec 20 2020 at 22:00)</a>:</h4>
<p>It seems like it should be emitting a typeck error instead of ICEing.</p>



<a name="220539897"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539897" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539897">(Dec 20 2020 at 22:15)</a>:</h4>
<p>Seems like an issue a beginner might somewhat easily run into?</p>



<a name="220539941"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539941" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539941">(Dec 20 2020 at 22:16)</a>:</h4>
<p>I don't think beginners usually start with recursive trait implementations :)</p>



<a name="220539946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539946">(Dec 20 2020 at 22:16)</a>:</h4>
<p>Yeah nevermind :D</p>



<a name="220539975"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220539975" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220539975">(Dec 20 2020 at 22:17)</a>:</h4>
<p>Is this a regression btw?</p>



<a name="220540017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540017">(Dec 20 2020 at 22:18)</a>:</h4>
<p>It is a regression ... from 1.24</p>



<a name="220540023"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540023" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540023">(Dec 20 2020 at 22:18)</a>:</h4>
<p>Damn, I can't read tonight, sorry :(</p>



<a name="220540035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540035">(Dec 20 2020 at 22:19)</a>:</h4>
<p>That's okay :)</p>



<a name="220540048"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540048" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540048">(Dec 20 2020 at 22:19)</a>:</h4>
<p>isn't that actually not related to recursive traits</p>



<a name="220540054"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540054" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540054">(Dec 20 2020 at 22:20)</a>:</h4>
<p>I don't actually understand what's going on <span aria-label="laughing" class="emoji emoji-1f606" role="img" title="laughing">:laughing:</span></p>



<a name="220540086"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540086" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540086">(Dec 20 2020 at 22:20)</a>:</h4>
<p>but instead with trait objects for <code>Fn() -&gt; UnsizedTy</code>?</p>



<a name="220540102"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540102" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540102">(Dec 20 2020 at 22:20)</a>:</h4>
<p>which tries to create a shim for the trait object</p>



<a name="220540106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540106">(Dec 20 2020 at 22:20)</a>:</h4>
<p>which tries to create a function with an unsized return type which doesn't work</p>



<a name="220540111"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540111" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540111">(Dec 20 2020 at 22:20)</a>:</h4>
<p><code>P-medium</code></p>



<a name="220540115"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540115" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540115">(Dec 20 2020 at 22:21)</a>:</h4>
<p>imo</p>



<a name="220540122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540122">(Dec 20 2020 at 22:21)</a>:</h4>
<p>Sounds good to me</p>



<a name="220540128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540128">(Dec 20 2020 at 22:21)</a>:</h4>
<p>so these impls/function can actually never be used as they would need a function returning an unsized type which can't exist</p>



<a name="220540168"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540168" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540168">(Dec 20 2020 at 22:22)</a>:</h4>
<p>so at least we don't break anything that should be working here</p>



<a name="220540169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540169">(Dec 20 2020 at 22:22)</a>:</h4>
<p>afaict</p>



<a name="220540175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540175">(Dec 20 2020 at 22:22)</a>:</h4>
<p>Issue <a href="https://github.com/rust-lang/rust/issues/58355">#58355</a>'s prioritization request has been removed.</p>



<a name="220540187"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540187" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540187">(Dec 20 2020 at 22:23)</a>:</h4>
<p>Done</p>



<a name="220540196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540196">(Dec 20 2020 at 22:23)</a>:</h4>
<p>Phew, now only 9 issues left to prioritize <span aria-label="sweat smile" class="emoji emoji-1f605" role="img" title="sweat smile">:sweat_smile:</span></p>



<a name="220540234"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2358355%20Compiler%20panic%20when%20implementing%20recurs%E2%80%A6/near/220540234" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2358355.20Compiler.20panic.20when.20implementing.20recurs.E2.80.A6.html#220540234">(Dec 20 2020 at 22:24)</a>:</h4>
<p>Let's do it</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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